Sound attenuating improvements for foundry molding machines

ABSTRACT

Jolt foundry molding machines incorporating specially constructed jolt impact receiving surfaces and exhaust and valve systems which achieve the required jolt impact to make satisfactory foundry molds while nevertheless attenuating the noise normally produced by such machines as required by the Occupational Safety &amp; Health Act Standards.

United States Patent Blower et a1. 1 1 Nov. 4, 1975 SOUND ATI'ENUATINGIMPROVEMENTS 2,561,726 7/1951 (3116mm 181/36 R FOR FOUND MOLDINGMACHINES 2,984,529 5/1961 Dailey 1 1 92/85 3170,3175 9/1966 Young 1 1 14 4 164/206 1 lnvemorsl Warren Blower, Brecksvllle; 3,450,037 6/19691161mm et 211.1 ,1 92/85 Harry R. Nara, Novelty, both of 3.53754311/1970 011381 181/36 A 01110 3,589,432 6/1971 Miller .1 164/393,658,118 4/1972 Abraham 164/39 [73] Asslgneel The sherwln-wllllamsCompanh 3,703,125 11/1972 Pauliukonis .1 92/249 Cleveland, 011103,724,502 4 1973 Hayner .4 181/36 R [22} Filed: Dec. 12, I972 FOREIGNPATENTS OR APPLICATIONS [21] Ap l. No.: 314,377 863.078 3/1961 UniICdKingdom 164/197 610,265 1/1932 German 164/206 52 us. 01 164/206;164/197; 91/216 B; Emmmekpaul E. Maslousky 91625; 92/85? 181/36 RArtur/1e1 Agem, or Firm-D0nr1el1y, Maky, Renner & (51] Int. Cl. ,1 B22C15/18; B22C 15/14; Om)

FO1B15/O0;F01L 21/02 [58] Field of Search 92/85. 117 R, 217. 250, 7 AB TT 92/249;91/216 B,216 R,216 A. 325; [5 I S B [64/206, 2031 39 261, 196197; 181/36 A Jolt foundry m0l d1ng machn es mcorporatmg specially 36 R,7! constructed olt lmpact recewmg surfaces and exhaust and valve systemswhich achieve the required jolt im- [56] References Cited 56c; t0 nxikeSiIISfHfiiOT) feundry moulds whjjle nave:-

eess a enua mg e no1se norma y pro uce y UNITED STATES PATENTS suchmachines as required by the Occupational Safety 989,971 4/1911 Herman164/206 & Health Act Standards, 1,459,221 6/1923 Krause 164/206 2,499018 2/1950 Christiano .1 181/71 26 Claims, 8 Drawing Figures -85 j I-78- 73- f l 87 74- Z 86 m 77 U.S. Patent Nov. 4, 1975 Sheet 2 of63,916,982

US. Patent Nov. 4, 1975 Sheet 3 of6 3,916,982

US. Patent Nov. 4, 1975 Sheet 4 of6 3,916,982

U.S. Patent Nov. 4, 1975 Sheet 5 Off) 3,916,982

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SOUND AI'IENUATING IMPROVEMENTS FOR FOUNDRY MOLDING MACHINES Thisinvention relates generally as indicated to sound attenuatingimprovements for foundry jolt molding machines and more particularly toimprovements in the construction of the strike or impact surfaces ofsuch machines as well as improvements in the exhaust and valve systems.

Foundry jolt molding machines normally operate at sound levels in therange of I to I decibels A"Scale (dbA). Most sound in such machines isnor mally created by two sources, the first being the metalto-metalstrike of the jolt impact, while the second is the air exhaust, airunder pressure being required to operate the jolt mechanism and othercomponents of the machine.

Foundry jolt molding machines nomially involve relatively moving massivemetal parts which impact against each other to obtain the jolt action.Jolt impact surfaces have in the past been provided with wearresistant,non-metallic coverings. These have not appreciably affected the soundlevels of the operation of the machines.

Applicants have found that by providing the jolt impact surfaces of thesqueeze ram or jolt ram with specially constructed elastomeric inserts,the noise level attributable to the jolt impact can be significantlyreduced while still nonetheless providing sufiicient impact forces toobtain dense, firm and uniformly packed foundry molds of the highestquality. In the case of the jolt ram which normally provides a centerstrike for the sand-filled flask supporting table, a large volumeelastomeric insert is provided in the ram to receive the impact. In thecase of an annular or outside strike with the table dropping onto thesqueeze piston, a relatively large volume elastomeric ring is provided.It has been discovered that the hardness of the elastomeric materialutilized should vary inversely to the area of the strike impact. Forexample, when the strike is on an an nular ring, the area of the strikeis substantial and the material should normally be fairly soft.Conversely, when the strike is in the center of the table or squeezehead, the area of impact is relatively small and the hardness of thematerial should be significantly increased. Not only must the hardnessand volume of the insert material be carefully controlled but thematerial itself must be carefully selected to avoid undue softening andwear upon repeated impacting in operation. The volume of the insert isalso a factor in dissipating heat resulting from repeated impactingwhich can cause softening.

In the exhaust system special mufflers or sound filters are employed inconjunction with specially designed porting for the exhaust, the latterpreferably leading to an expansion chamber before being ported to atmosphere.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features here inafter fully described, the followingdescription and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative however,of but a few of the various ways in which the principles of theinvention may be employed.

IN SAID ANN EXED DRAWINGS:

FIG. I is a fragmentary vertical section of one embodiment of thepresent invention illustrating a machine providing both an anvil joltand shockless jolt during squeeze;

FIG. 2 is a fragmentary vertical section taken sub stantially on theline 22 of FIG. I illustrating the exhaust expansion chamber in thehousing with laterally extending exhaust ports therein;

FIG. 3 is a vertical section of a machine similar to that of FIG. I butillustrating a different exhaust porting arrangement for the jolt withthe exhaust ports extending through the annular anvil jolt strike ring;the exhaust porting also being connected to the lower chamber;

FIG. 4 is a horizontal section taken substantially on the line 44 ofFIG. 3 illustrating the arrangement of the exhaust ports in the strikering;

FIG. 5 is a vertical section taken through the table of a somewhatlarger machine of the type which may be used, for example, in automaticlines;

FIG. 6 is a vertical section of a machine having a modified form ofsqueeze cylinder ram providing both an annular outside anvil jolt and acenter strike shockless jolt;

FIG. 7 is a fragmentary vertical section of an over head squeeze headincorporating a jolt ram and provided with some of the sound attenuatingimprovements of the present invention; and

FIG. 8 is a vertical section of a machine similar to that of FIG. 6 bututilizing the center strike only for both anvil jolt and shockless joltduring squeeze.

In describing the various embodiments of the present inventionparticular attention will be paid to the sound attenuating improvementsincorporated in the various machines illustrated and the details of suchmachines will be described only to the extent thought necessary toprovide the proper environment for the improvements of this invention.

With reference to FIG. I there is illustrated a machine having a base 10which includes an upstanding cylindrical housing 11 in which is mountedsqueeze piston 12. Such squeeze piston includes an upstanding cylindrical portion I3. Projecting into the cylindrical extension ]3 ofthe squeeze piston I2 is a cylindrical extension 14 depending from table15. The table is adapted to support a sand-filled pattern containingflask. Normally a squeeze head is positionable above the table, suchsqueeze head engaging the sand within the flask as the table is elevatedto form the foundry mold.

Positioned interiorly of the table cylindrical extension 14 is a ram 16which includes a lower reduced di ametcr extension I7 which extendsthrough a central opening in the squeeze piston formed by the outwardlyextending central cylindrical portion 18. The extension I7 in the downposition of the table is supported on the base 10 and there is provideda slight clearance indicated at 20 between the top of jolt piston andthe underside of the table thcreabove. The table in such down positionis supported solely on the annular top of the cylindrical extension 13of the squeeze piston. In such down position the squeeze piston 12 isbottomed on the housing It) as indicated at 21.

In operation, to obtain an anvil jolt or a dropping of the table againstthe machine base, air under pressure is supplied through passage 23 inthe table which enters chamber 24. In the down position of the tablepoppet valve member 25 is in its up position compressing spring 26, thespring and valve member surrounding poppet guide 27, the cap 28 of whichis secured to the table by fasteners 29. In the down position of thetable the valve member 25 is unseated from the shoulder 30 andaccordingly air from the passage 23 will pass into chamber 31 betweenthe ram 16 and the table 15. When air is thus admitted to the chamber 31the table is lifted off strike ring 32 on the top of the squeeze pistoncylindrical extension 13. As the table elevates the spring 26 will causethe poppet valve member to move downwardly against the seat closing theair inlet to the chamber 31. Even though the valve member 25 is closed,the table will continue upwardly due to both the pressure in chamber 31and the momentum of the table. The table continues upwardly untilannular slot 34 in ram 16 communicates with transverse exhaust ports 35in the table cylindrical extension 14. The annular groove 34 is incommunication with the chamber 31 through a plurality of vertical slots36. The exhaust ports 35 in the table cylindrical extension 14 are incommunication with vertically elongated shallow groove 37. Such grooveextends downwardly from the exhaust ports 35 and provides communicationbetween exhaust ports 35 and exhaust ports 38 in the squeeze pistoncylindrical extension 13. The exhaust ports 38 communicate with afurther elongated groove 40 in the outside face of the extension 13 ofthe squeeze piston. The purpose of the elongated slot 40 is to providecommunication between the exhaust ports 38 and exhaust slots 41 in thehousing wall 11. Such slots 41 are three in number as seen in FIG. 2 andprovide communication between the elongated groove 40 and exhaustchamber 42. The side walls 43 and 44 of the exhaust chamber are providedwith enlarged exhaust ports 45 and 46, respectively, which are coveredby exhaust screens or mufflers 47 and 48, respectively, each of which issecured in place by screen clamp ring 49 which is in turn secured by thefasteners 50. The exhaust screens or mufflers may be of the compressedmetal fiber type which have been found effective to reduce air exhaustnoise in combination with the exhaust arrangement shown.

When the annular groove 34 communicates with the exhaust port 35, airfrom the chamber 31 will then exhaust to atmosphere through the exhaustchamber 42. The table then drops onto the strike ring 32. When the tabledrops the valve member 25 is again opened repeating the jolt operationas long as the jolt valve is open supplying air pressure through theline 23. In the illustrated embodiment, the valve member 25 will travelapproximately three-eighths of an inch to its closed position whilethere is approximately 1 inch of travel required to providecommunication between the slot 34 in the jolt ram and the exhaust ports35. This arrangement reduces the volume of air required to perform thejolt action and accordingly also reduces exhaust noise.

Now. to jolt during squeeze, air is supplied through pipe flange 52pressurizing the chamber 53 beneath the squeeze piston 12 throughpassage 54. This elevates the squeeze piston and of course the table 15supported on the strike ring 32. Jolt ram 16 is also elevated by the airpressure within the chamber 53 since the extension 17 thereof is exposedto the pressure within such chamber.

This of course will move the jolt ram against the bottom of the table 15opening the poppet valve member 25. Again when air is supplied throughthe passage 23 to the chamber 31 the jolt ram 16 will descend firstclosing valve member 25 and then providing communication between theslot 34 and the exhaust ports 35 venting the chamber 31. The squeezepressure beneath the jolt ram extension 17 will then cause the ram tomove upwardly striking the bottom of the table on the underside of thefrusto-conical projection 55. This action will continue as desired asthe table is elevated against the squeeze head compressing the sandwithin the flask supported on the table.

The exhaust system of the machine of FIG. 1 which utilizes: the shortstroke poppet 25; a reduced volume chamber 31 with vertical slots and anannular slot 34 comprising a part of that chamber; a plurality ofexhaust ports 35 (in the illustrated embodiment preferably six innumber); the exhaust ports 38 and the exhaust slots 41 communicatingwith the exhaust chamber 42 provided with cover 56; and the enlargedlater ally extending exhaust ports 45 and 46, has been found effectivelyto reduce the noise level of such machine caused by the jolt airexhaust. For comparative purposes references may be had to US. Pat. No.3,658,1 18 to Abraham dated Apr. 25, 1972, showing an exhaust system ofa prior art machine. While all of the above factors are believed tocontribute to the reduced noise level, one point of some significance isbelieved to be the ratio of the cross-sectional area of the exhaustports 35 as compared to the cross-sectional area of the exhaust ports 45and 46. In the illustrated embodiment the latter two provide across-sectional area of approximately 14.1 square inches while thecross-sectional area of the six exhaust ports 35 provide acrosssectional area of approximately 4.7 square inches. This provides anarea enlargement in a ratio of approximately three to one.

To reduce the noise level normally generated by the usual metal-to-metalimpact of a jolt mechanism, the strike ring 32 is made of a urethaneelastomer and includes a mounting ring 58 which is secured to the top ofthe squeeze piston extension 13 by suitable fasteners 59. To reduce thenoise level of the center strike, the jolt ram 16 is provided at its topwith a cavity 61 in which is secured a large volume molded urethaneinsert 62. The insert is secured in place by a retaining ring 63 whichfits over the shoulder 64 on the insert. The insert is provided with afrusto-conical top projection 65 having the same area as the projection55 on the table. A tapped aperture 66 is provided in the top of theinsert to facilitate the insertion of a lifting eye so that the insertmay be readily removed. In the illustrated embodiment the insert 62 may,for example, have a diameter of approximately 6 inches and also a heightof approximately 6 inches. Thus the insert is quite massive. The volumeof the urethane insert 62 is believed to create some form of heat sinkwhich in combination with the ram structure maintains the insertsufficiently cool to prelude undue softening. For example, a urethaneinsert pulled after use has felt cold on the outside but the center ofthe insert was measured at about 200 Farenheit by the use of athermocouple. Jolt air passing from the chamber 31 down the verticalslots 36 and into the annular slot 34 apparently extracts heat from theinsert, the clearance between the insert and the surrounding jolt rambeing just sufficient to insert and remove the insert 62.

For the center strike insert 62 which has a relatively small strike areait has been found that a relatively high hardness is required of fromabout 65 to 72 on the Shore D scale and preferably about 70 while thestrike ring 32, having a much larger impact area may have a hardness ofapproximately 60 to about 95 on the Shore A scale. This is of courserelatively soft. With the hardnesses noted it has been found thatsufficient impact is still obtained to produce high quality molds whilereducing the noise level to less than 90 decibels (dbA). As indicated,normal metal-to-metal impact in such machines generally run from around110 to I decibels (dbA).

The inserts of this and subsequently described embodiments mayincorporate suitable heat transfer fillers in suitable amounts(approximately 25-50%). Fillers which have been found to functionacceptably are lami nar fillers such as aluminum chips, iron or flakealuminum. Also acceptable are graphite granules or coarse bronze wool,for example. It has been found that the insert can be molded in stepswith the heat transfer fill ers placed alternately between the steps.For example, the uncured elastomer may be poured in the mold to acertain height and then aluminum chips may be Iayed on top of thatportion poured. The pouring and placement of the filler is thenalternated until the insert is completely molded. Circular discs ofaluminum or cop per screen of suitable mesh to permit the elastomer toflow therethrough may be used. In any event, the filler is then confinedto vertically spaced horizontal layers. It is believed that such fillersact to absorb and transmit heat from the center of the insert whichresults from the hysteresis loss of the material. The temperature is ofcourse a factor in the properties of the material and the fillers arebelieved to maintain the properties at acceptable levels.

In FIGS. 3 and 4 there is illustrated another embodiment of theinvention utilizing a different exhaust system to obtain the requisitenoise control. In such embodiment the machine includes a housing 70.squeeze piston 71 mounted therein for vertical reciprocation, table 72having a cylindrical skirt 73 telescoped into the cylindrical extension74 of the squeeze piston and jolt ram 75 mounted for verticalreciprocation in the table extension 73. The jolt ram includes a reduceddiameter extension 76 extending through the squeeze piston so that thelower end of the extension 76 is exposed to the chamber beneath thesqueeze piston. The jolt ram is provided with a cavity 77 in which issecured the large volume urethane insert 78 while the top of thecylindrical extension 74 of the squeeze piston 71 is provided withurethane strike ring 79 secured through mounting ring 80 by thefasteners 81.

Air for the jolt action is obtained through the poppet valve assembly82. As the table elevates, the air from the chamber 83 above the joltram passes downwardly through slots 84 into the annular slot 85 andoutwardly through exhaust ports 86 in the table extension 73.

The exhaust ports 86, which again may be six in number as in the FIG. Iembodiment, communicate with an annular groove 87 in the interior of theextension 74 of the squeeze piston 71. The extension 74 also has aseries of vertical grooves 88 therein which extend vertically along theinterior thereof. the lower ends communicating with the chamber 89beneath the table extension 73 and the enlargement of the jolt ram 75.As seen more clearly in FIG. 4, three of the vertical slots 88communicate with paired exhaust ports seen at 91. Such exhaust portsextend vertically in the annular strike ring 79 and the mounting ringwith the latter being utilized to hold muffler screens 92 in place. Itwill be appreciated that additional exhaust ports may be providedextending vertically through the strike ring 79. Such exhaust ports willof course be opened as the table is elevated from the strike ringpermitting air to escape beneath the relatively shallow skirt 93. Thecombination of the muffler screens 92, which are the same type asemployed in the FIG. I embodiment, together with the large number ofexhaust ports has been found effectively to reduce the air exhaustnoise.

One point of note which is illustrated perhaps most clearly in FIG. 4 isthat the urethane large volume insert 78 which receives the centerstrike of the jolt ram is provided with a transverse top slot 94 whichprecludes an air seal between the ram and the underside of the table.

Referring now to FIG. 5 there is illustrated the head ofajolt andsqueeze machine which may be utilized for example in automatic lines.The machine includes a table 96 which is supported on springs, notshown, on vertically movable guide head 97 which is in turn supported onthe upper end of tubular piston rod 98. The piston rod 98 extendsthrough fixed cylinder head 99 from the cylinder I00 of the verticallyextending piston cylinder assembly by which the table 96 is raised andlowered.

.lolt guide pins I02 and I03 are secured to the guide head 97 and extendthrough suitable bushings in both the table and the cylinder head asindicated at 104 and 105, respectively. A jolt ram 106 includes a lowerre' duced diameter extension I07 which is spring supported and pilotedin the tubular rod 98. The jolt ram is mounted in cavity I08 in thetable and a suitable piston ring is provided indicated at 109. The tableincludes a cylindrical skirt I I0 formed by the cavity 108. Air for thejolt is supplied through the poppet valve assembly III pressurizingchamber 112. The chamber I I2 includes vertical passages I I3communicating with annular groove II4 so that when the table and rammove relative to each other and the groove 114 is exposed to exhaustports I IS the chamber "2 will be exhausted. The exhaust ports I I5 areclosed by plugs 1 l6 and inverted T-passages I17 connect the exhaustports [I5 to chamber "8 through their open legs.

The chamber 118 is formed by ring II9 mounted on annular plate I20secured to the guide head 97. The top of the annulus H9 is provided witha beveled ring I2], the ID. of which has a rather close clearance withthe OD. of the skirt H0. The annulus H9 is provided with a plurality ofexhaust ports I22 each of which has secured therein muffler screens I23of the type illustrated in the embodiments of FIGS. I and 3.

Jolt ram I06 is provided with a large volume ure thane insert seen atI24 held in place by the retaining ring I25 as in the embodiments ofFIGS. I and 3. In this embodiment the insert I24 is provided with twodia metrical intersecting passages I26 and 127 at the bottom thereof.Each of the four radially extending passages thus formed is providedwith two vertically extending passages as seen at 128 and 129, or eightsuch vertical passages altogether. .Iolt air from the chamber H2 isaccordingly required to pass downwardly through the insert to exhaustthrough passages l 13 during jolt. This accordingly more directlyremoves heat from the insert which would be generated by repeated joltimpact.

The chamber 118 acts as in the FIG. 1 embodiment as an expansion chamberreducing the exhaust pressure through the ports 122 and together withthe muffler screens in a series of exhaust ports substantially reducesthe noise level caused by the exhaust. For example, there may be 12exhaust ports 122 in the annulus 119 thus increasing the cross-sectionalarea of the ex haust ports by the factor of approximately 3 to lindicated above. The machine of FIG. has been found to produce highquality foundry molds with substantially reduced noise levels.

in FIG. 6 the machine includes a table 132 having depending cylindricalextension 133 which tits within cylindrical liner 134 mounted on andsecured to shoulder 135 on the interior of the cylindrical extension 136of the squeeze piston 137. The cylindrical extension 136 includes a topflange 138 which in the table down position seats on the top [39 of thecylindrical portion [40 of the base 141.

A jolt ram 143 in the table down position is supported on ram extension144 which extends through sleeved aperture 145 in the piston 137. Theend of the extension is provided with a lip [46 which precludes theextension from popping through the aperture when the squeeze piston ispressurized.

For jolt action air is admitted from the passage 148 through unseatedpoppet valve 149 into chamber 150 above the jolt ram. In the table downposition. the urethane insert 15] engages the poppet valve member 149unseating the same. Jolt air pressure in the chamber 150 elevates thetable until groove [52 communicates with exhaust ports 153 in the tableextension 133 per mitting the jolt air to escape into vertical grooves154. The vertical grooves 154 are provided with ports 155 communicatingwith annular chamber I56 which in turn communicates through passages 157with chamber [58 beneath the table extension 133 and the jolt ram 143.

The chambers I58 and 156 act as expansion chambers reducing the airpressure impact on exhaust ports 160, each of which is provided with amuffler screen as indicated at 161. in the illustrated embodiment ofPK]. 6, there may. for example. be eight such exhaust ports 160. Suchexhaust ports permit the air to escape into chamber 162 and then overthe top of the annular strike ring 163 to atmosphere. Radial grooves 164may be provided in the top of the strike ring to exhaust chamber [62during simultaneous jolt and squeeze. Such ring is held to the flange138 of the squeeze piston by fasteners 165 extending through mountingring 166.

A jolt guide pin [67 is mounted in table 132 and ex tends into bushing[68. A limit pin [69 is mounted in the cylindrical extension 140 of base141 extending into closed-end slot in the CD. of cylindrical extension]36 of squeeze piston 137. The pin 169 pre cludes ovcr-stroke of thetable. Additionally, overstroke ports may be provided in the liner topreclude the table from popping out.

The large volume urethane insert 151 includes a somewhat higherfrusto-conical portion 172 than the inserts of the other embodiments.such frusto-conical portion projecting from a cylindrical base 173'.retaining ring 174 engaging the top of the base to hold the in sert inplace in its cavity. This permits the vertical grooves 175 extendingbetween the chamber 150 and the annular groove 152 to be foreshortened.The insert 151 is also provided with the threaded aperture 176permitting a lifting eye to be inserted so that the insert may beremoved. Transverse passage l77 communicating with the aperture 176serves the same function as the transverse slot 94 seen in FIG. 4.

In the operation, with the table down. the table will be jolted on theannular strike ring 163 due to the clearance between the top of thecenter insert 151 and the underside of the table. At the peak of thestrike the compression of the ring 163 may also cause contact withinsert 151. When the squeeze air pressure is supplied through port 179,the table will be elevated and as the pressure increases to a certainpreset value the ram extension 144 will be elevated to the extentpermitted by the lip 146. This will cause the insert [51 to engage theunderside of the table and continued jolting during elevation or squeezeis accomplished on the center insert with the ram rebounding due tosqueeze air pressure.

It will. of course. be appreciated that the chamber I58 may bepressurized with an imperforate piston [37 and without the extension 144so that the ram 143 will rebound on a pillow of air within the chamber158. To control the pressure within chamber 158, a pressure control linemay be provided through port 157. Such line may lead to a servo valvewhich is operative in response to the position of the table 132.

Referring now to the embodiment of FIG. 7, there is illustrated asqueeze head against which the sand filled flask is elevated to ram afoundry mold therein. The squeeze head shown generally at 184 includes aperipheral peen strip 185 and a central pouring basin mold imprinter186. Both are mounted on plate I87 readily removably secured throughbrackets 188 to vertically extending plates 189. Such plates extenddownwardly from the bottom 190 of cylindrical housing 191, the upper endwhich is closed by plate 192.

The housing 191 is supported on compression springs 193 supported onwashers 195. in turn on nuts 1%. secured to the lower ends of supportrods 197. Such rods are secured to fixed head frame 198 and extendthrough bushings 199 and 200 in laterally projecting ears on thecylindrical housing 191. The top plate 192 of the housing is providedwith a FABREEKA pad 202 adapted to engage the underside of the fixedframe 198. Accordingly, the squeeze head is adapted to move downwardlyagainst the compression of the springs 193. but is limited in its upwardmovement.

Inside the cylindrical housing 191 is a large volume jolt ram 203 whichis mounted for vertical reciprocation in the housing. The ram isprovided with a cavity 204 in which is positioned a large volumeelastomeric urethane insert 205 having a projection 206 thereon adaptedto engage projection 207 on the squeeze head bottom plate 190.

To obtain a jolting action, air is supplied through the port 208 to thechamber beneath the ram 203 elevating the same until exhaust ports 209are uncovered directly exhausting the air beneath the ram. The chamberabove the ram may be vented to atmosphere through ports 2l0. The ram. ofcourse. traps air above the exhaust ports to assist in rebounding theram against the squeeze head.

In the illustrated embodiment. there may be 12 exhaust ports 209. somebeing fitted with muffler screens indicated at 21 I. while others may betitted with the cylindrical baffle-type mufflers seen at 212. In anyevenL the combination of the large number of exhaust ports. togetherwith the mufflers. reduces the exhaust air noise to a satisfactory levelwhile the large volume ram insert 295 reduces the metal to metal impactnoise nor mally present.

FIG. 8 is an embodiment of the invention fairly similar to that of FIGv6. but utilizing the center strike ofthe table and jolt ram for bothanvil jolt and shockless jolt during the squeeye. The machine includesbase 215 liming upstanding cylindrical housing 216 in which squeezepiston 217 is mounted for vertical reciprocation. The squee/e pistonincludes an upstanding cylindrical portion 218. the top of whichterminates in flange 219 which bottoms on the top of the housing Thesqueeze piston includes a liner 221 in which the ex tension 222 oftl'ictable 223 Is mounted. Jolt guide pins 224 extend from the table into theliner.

A poppet valve assembly 225 admits air to chamber 226 above jolt ram 227inside the table extension 222. The jolt ram includes as a separate itemextension 228 extending through sleeved aperture 229 in the removablebottom plate 230 ofthe piston 217. The extension includes a lip 23!precluding the same from popping through the sleeved aperture 229. Theextension is sup orted on large annular spring plate 232 in the downposition ofthe table. the latter being supported on elastomcric ring 233which may be urethane of a suitable hardness. l'hc plate is held incentered position by a guide pin 234, the head of which precludes theplate from bouncing upwardly excessively or being lifted by squeeze airpressure. The plate is not otherwise held within the machine. Theextension 228 is provided with a suitable aperture 236 to provide asuitable clearance between the extension and the guide pin head.

in the down position of the table. the table is so; ported on the insert237 secured in the jolt ram 227 by the retaining ring 238. When air isadmitted through the poppet valve assembly 225 to the chamber 226 abovethe jolt ram 227, the table elevates until the exhaust ports 240 areexposed to the chamber. where-- upon the table drops providing an anviljolt impact on the top of the insert 237. The impact is transmittedthrough the jolt ram to the ram extension 228 and through the largediameter spring plate 252 and the rin 233 to the housing or base 2l5.The large diameter spring plate. which may be 1090 steel. heat treated.thus absorbs. transfers and distributes the relatively concentratedimpact as a smaller load to a much larger area permitting the base totake the repeated impact load During squeeze. the squeeze piston 217elevates to pick up the table at the flange clearance 241. Air pres surebeneath the piston also elevates the extension 22% and the jolt ram 227.Jolt during squeeze is obtained in the same manner as in the FIG tiembodiment.

Again as in the llti. h embodiment. there may be six such exhaust ports240, each provided with a mulflcr screen 24*. The exhaust ports lead tovertical grooves 243 in the table extension and the port to atmosphere.as indicated at 244. It will of course be understood that the sameexhaust system as provided in FIG. (1 may be used in the H0. 8embodiment with the screened exhaust pvrts being in the liner from anexhaust system Iii F ll

also communicating with the chambers 245 and 246 the latter in thisembodiment being normally vented through the passages 24']. In anyevent. the urethane insert 237 may be the same as the insert 15! in theFIG. embodiment. and with such large volume insert together with theexhaust system. machines are provided which produce excellent foundrymolds at much reduced noise levels.

What is claimed is:

I. In a foundry jolt molding machine having a table adapted to support asand-tilled lTasl-t. a pneumatically operated jolt mechanism in saidtable including a verti cally movable jolt ram. the improvementcomprising exhaust system porting means for said 5 ilt mechanismprogressively enlarging in crust-sectional area towards a plurality ofexhaust ports at atmosphere thereby substantially reducing the noiselevel of the machine. and an expansion chamber in said system betweensaid jolt mechanism and said exhaust ports operative to reduce thepressure of the exhausting air. said expansion chamber being formed inpart by a portion of the un dersidc of said jolt ram.

2. A machine as set forth in claim 1 including sound absorbing screenson each of the exhaust ports of such system.

3. A machine as set forth in claim I including piston and cylinder meansoperative vertically to elevate said table. and a further expansionchamber in such system provided extcriorly of the cylinder of saidpiston.

4. A machine as set forth in claim 3 wherein said further expansionchamber includes two relatively large laterally extending final exhaustports.

5. A machine as set. forth in claim 3 including slot meansinterconnecting said jolt mechanism and such further expansion chamberat all vertical positions of elevation of said table.

6. A machine as set forth in claim I wherein said jolt mechanismincludes a cylindrical extension on said table and said jolt ramreciprocally mounted therein. and poppet valve means operative to openby contact between said ram and table. the movement of said poppct valvemeans being limited to reduce the volume of air required for said joltmechanism.

7. A machine as set forth in claim I wherein the en largemcnt incross-sectional area towards the atmosphere is approximately in a ratioof 3 to I.

St In foundry jolt molding machine. having a verti cally movable table.means to elevate said table and then drop the same to obtain a joltstrike. the improvement comprising an elastorneric sound attenuatingin-- sert means against which said table is dro ed. the hardness of saidinsert means being inversely reiated to the area of the strikethereagainst.

9. A machine as set forth in claim 8 wherein said inscrt means includesa heat absorbing and transmitting tiller material.

It]. A machine as set forth in claim 8 wherein said elastomeric soundattenuating insert means includes an annular ring having a large impactarea. said ring being relatively soft.

II. A machine as set forth in claim I" wherein said ring has a durometerhardness on the Shore A scale of approximately 60 to about 95.

12. A machine as set forth in claim 8 wherein the said elastomeric soundattenuating insert means including an insert in the center of the tableand has a relatively small strike area. said insert being relativelyhard.

13. A machine as set forth in claim 12 wherein said insert has adurometer hardness on the Shore D scale of approximately 70.

14. A machine as set forth in claim 3 wherein said insert means includesan insert of solid polyurethane of substantial volume.

15. A machine as set forth in claim 8 wherein said insert means includesan insert of solid polyurethane of substantial volume. and meansoperative to cool said insert by the passage of machine exhaust airthcreadjacent.

16. A machine as set forth in claim 8 including a reciprocable jolt ramin the center of the table. said insert means including an insertmounted in the end of said ram facing said table and projecting fromsaid ram to receive the table strike thereagainst.

17. A machine as set forth in claim 16 wherein said insert is a largevolume of solid polyurethane held in place by a retaining ring.

18. A machine as set forth in claim 8 including air passages extendingthrough a part of said insert means for cooling the same.

19. In a foundry jolt molding machine comprising a table and jolt rammounted for relative movement to obtain jolt impact. the improvementcomprising a large volume elastomeric insert in said jolt ram to receivethe impact. whereby such machine will operate to produce high qualityfoundry molds at reduced noise levels. said table and jolt ram being airoperated to obtain such jolt impact. and means to pass such air adjacentsuch insert to prevent overheating the same.

20. A machine as set forth in claim 19 wherein said insert is solidpolyurethane having a hardness of approximately 60 to 75 on the Shore Dscale.

2|. A foundry jolt molding machine comprising a table and a jolt rammounted in said table for relative movement, means to pressurize the endof the ram facing the table relatively to move said ram and said table.means to vent the pressurized end of said ram through a plurality ofexhaust ports to bring the table and ram together for ajolt impact. suchram having a large volume elastomeric insert therein to receive the joltimpact. whereby such machine will operate to produce high qualityfoundry molds at a noise level of less than 90 dbA (A scale). saidchamber formed by the end of the ram facing the table and including aplurality of passages adjacent the insert to facilitate the dissipationof heat therefrom.

22. A machine as set forth in claim 21 wherein said insert is solidpolyurethane having a hardness of approximately on the Shore D scale.

23. In a foundry jolt molding machine. having a vertically movabletable. means to elevate said table and then drop the same to obtain ajolt strike. the improvement comprising an elastomeric sound attenuatinginsert means against which said table is dropped. the hardness of saidmeans insert being inversely related to the area of the strikethereagainst. said elastomeric sound attenuating insert means includingan annular ring having a large impact area. said ring being relativelysoft. and exhaust air ports extending through said annular ring.

24. A machine as set forth in claim 23 including muffler screens in saidexhaust air ports.

25. in a foundry jolt molding machine comprising a table and jolt rammounted for relative movement to obtain jolt impact. the improvementcomprising a large volume elastomerie insert in said jolt ram to receivethe impact. whereby such machine will operate to produce high qualityfoundry molds at reduced noise levels. and an exhaust system portingmeans for said table and jolt ram progressively enlarging incross-sectional area towards atmosphere thereby substantially reducingthe noise level of the machine.

26. A machine as set forth in claim 25 including an expansion chamber insuch exhaust system to reduce the air pressure of the exhaust.

1. In a foundry jolt molding machine having a table adapted to support asand-filled flask, a pneumatically operated jolt mechanism in said tableincluding a vertically movable jolt ram, the improvement comprisingexhaust system porting means for said jolt mechanism progressivelyenlarging in cross-sectional area towards a plurality of exhaust portsat atmosphere thereby substantially reducing the noise level of themachine, and an expansion chamber in said system between said joltmechanism and said exhaust ports operative to reduce the pressure of theexhausting air, said expansion chamber being formed in part by a portionof the underside of said jolt ram.
 2. A machine as set forth in claim 1including sound absorbing screens on each of the exhaust ports of suchsystem.
 3. A machine as set forth in claim 1 including piston andcylinder means operative vertically to elevate said table, and a furtherexpansion chamber in such system provided exteriorly of the cylinder ofsaid piston.
 4. A machine as set forth in claim 3 wherein said furtherexpansion chamber includes two relatively large laterally extendingfinal exhaust ports.
 5. A machine as set forth in claim 3 including slotmeans interconnecting said jolt mechanism and such further expansionchamber at all vertical positions of elevation of said table.
 6. Amachine as set forth in claim 1 wherein said jolt mechanism includes acylindrical extension on said table and said jolt ram reciprocallymounted therein, and poppet valve means operative to open by contactbetween said ram and table, the movement of said poppet valve meansbeing limited to reduce the volume of air required for said joltmechanism.
 7. A machine as set forth in claim 1 wherein the enlargementin cross-sectional area towards the atmosphere is approximately in aratio of 3 to
 1. 8. In foundry jolt molding machine, having a verticallymovable table, means to elevate said table and then drop the same toobtain a jolt strike, the improvement comprising an elastomeric soundattenuating insert means against which said table is dropped, thehardness of said insert means being inversely related to the area of thestrike thereagainst.
 9. A machine as set forth in claim 8 wherein saidinsert means includes a heat absorbing and transmitting filler material.10. A machine as set forth in claim 8 wherein said elastomeric soundattenuating insert means includes an annular ring having a large impactarea, said ring being relatively soft.
 11. A machine as set forth inclaim 10 wherein said ring has a durometer hardness on the Shore A scaleof approximately 60 to about
 95. 12. A machine as set forth in claim 8wherein the said elastomeric sound attenuating insert means including aninsert in the center of the table and has a relatively small strikearea, said insert being relatively hard.
 13. A machine as set forth inclaim 12 wherein said insert has a durometer hardness on the Shore Dscale of approximately
 70. 14. A machine as set forth in claim 8 whereinsaid insert means includes an insert of solid polyurethane ofsubstantial volumE.
 15. A machine as set forth in claim 8 wherein saidinsert means includes an insert of solid polyurethane of substantialvolume, and means operative to cool said insert by the passage ofmachine exhaust air thereadjacent.
 16. A machine as set forth in claim 8including a reciprocable jolt ram in the center of the table, saidinsert means including an insert mounted in the end of said ram facingsaid table and projecting from said ram to receive the table strikethereagainst.
 17. A machine as set forth in claim 16 wherein said insertis a large volume of solid polyurethane held in place by a retainingring.
 18. A machine as set forth in claim 8 including air passagesextending through a part of said insert means for cooling the same. 19.In a foundry jolt molding machine comprising a table and jolt rammounted for relative movement to obtain jolt impact, the improvementcomprising a large volume elastomeric insert in said jolt ram to receivethe impact, whereby such machine will operate to produce high qualityfoundry molds at reduced noise levels, said table and jolt ram being airoperated to obtain such jolt impact, and means to pass such air adjacentsuch insert to prevent overheating the same.
 20. A machine as set forthin claim 19 wherein said insert is solid polyurethane having a hardnessof approximately 60 to 75 on the Shore D scale.
 21. A foundry joltmolding machine comprising a table and a jolt ram mounted in said tablefor relative movement, means to pressurize the end of the ram facing thetable relatively to move said ram and said table, means to vent thepressurized end of said ram through a plurality of exhaust ports tobring the table and ram together for a jolt impact, such ram having alarge volume elastomeric insert therein to receive the jolt impact,whereby such machine will operate to produce high quality foundry moldsat a noise level of less than 90 dbA (A scale), said chamber formed bythe end of the ram facing the table and including a plurality ofpassages adjacent the insert to facilitate the dissipation of heattherefrom.
 22. A machine as set forth in claim 21 wherein said insert issolid polyurethane having a hardness of approximately 70 on the Shore Dscale.
 23. In a foundry jolt molding machine, having a verticallymovable table, means to elevate said table and then drop the same toobtain a jolt strike, the improvement comprising an elastomeric soundattenuating insert means against which said table is dropped, thehardness of said means insert being inversely related to the area of thestrike thereagainst, said elastomeric sound attenuating insert meansincluding an annular ring having a large impact area, said ring beingrelatively soft, and exhaust air ports extending through said annularring.
 24. A machine as set forth in claim 23 including muffler screensin said exhaust air ports.
 25. In a foundry jolt molding machinecomprising a table and jolt ram mounted for relative movement to obtainjolt impact, the improvement comprising a large volume elastomericinsert in said jolt ram to receive the impact, whereby such machine willoperate to produce high quality foundry molds at reduced noise levels,and an exhaust system porting means for said table and jolt ramprogressively enlarging in cross-sectional area towards atmospherethereby substantially reducing the noise level of the machine.
 26. Amachine as set forth in claim 25 including an expansion chamber in suchexhaust system to reduce the air pressure of the exhaust.